Investigating Multi-Pivot Ensembling with Massively Multilingual Machine Translation Models

Fuente: arXiv
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Auteurs principaux: Mohammadshahi, Alireza, Vamvas, Jannis, Sennrich, Rico
Format: Preprint
Publié: 2023
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author Mohammadshahi, Alireza
Vamvas, Jannis
Sennrich, Rico
author_facet Mohammadshahi, Alireza
Vamvas, Jannis
Sennrich, Rico
contents Massively multilingual machine translation models allow for the translation of a large number of languages with a single model, but have limited performance on low- and very-low-resource translation directions. Pivoting via high-resource languages remains a strong strategy for low-resource directions, and in this paper we revisit ways of pivoting through multiple languages. Previous work has used a simple averaging of probability distributions from multiple paths, but we find that this performs worse than using a single pivot, and exacerbates the hallucination problem because the same hallucinations can be probable across different paths. We also propose MaxEns, a novel combination strategy that makes the output biased towards the most confident predictions, hypothesising that confident predictions are less prone to be hallucinations. We evaluate different strategies on the FLORES benchmark for 20 low-resource language directions, demonstrating that MaxEns improves translation quality for low-resource languages while reducing hallucination in translations, compared to both direct translation and an averaging approach. On average, multi-pivot strategies still lag behind using English as a single pivot language, raising the question of how to identify the best pivoting strategy for a given translation direction.
format Preprint
id arxiv_https___arxiv_org_abs_2311_07439
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Investigating Multi-Pivot Ensembling with Massively Multilingual Machine Translation Models
Mohammadshahi, Alireza
Vamvas, Jannis
Sennrich, Rico
Computation and Language
Artificial Intelligence
Machine Learning
Massively multilingual machine translation models allow for the translation of a large number of languages with a single model, but have limited performance on low- and very-low-resource translation directions. Pivoting via high-resource languages remains a strong strategy for low-resource directions, and in this paper we revisit ways of pivoting through multiple languages. Previous work has used a simple averaging of probability distributions from multiple paths, but we find that this performs worse than using a single pivot, and exacerbates the hallucination problem because the same hallucinations can be probable across different paths. We also propose MaxEns, a novel combination strategy that makes the output biased towards the most confident predictions, hypothesising that confident predictions are less prone to be hallucinations. We evaluate different strategies on the FLORES benchmark for 20 low-resource language directions, demonstrating that MaxEns improves translation quality for low-resource languages while reducing hallucination in translations, compared to both direct translation and an averaging approach. On average, multi-pivot strategies still lag behind using English as a single pivot language, raising the question of how to identify the best pivoting strategy for a given translation direction.
title Investigating Multi-Pivot Ensembling with Massively Multilingual Machine Translation Models
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2311.07439